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Journal of Paramedical Sciences (JPS) Winter 2014 Vol.5, No.1 ISSN 2008-4978 Effects of garlic supplementation on blood pressure Marjan Mahdaviroshan*,1, Javad Nasrollahzadeh2, Elham Khodadadi National Nutrition and Food Technology Research Institute, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Department of Clinical Nutrition & Dietetics, National Nutrition and Food Technology Research Institute, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Proteomics Research Center, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran *Corresponding Author: email address: mahdaviroshan@yahoo.com (M Mahdaviroshan) ABSTRACT Hypertension is one of the major risk factor for cardiovascular morbidity and mortality One of primary management of hypertension include dietary changes which could incorporate dietary supplementation ,also use of non pharmacological treatment options is high in patients with high blood pressure Garlic has played an important dietary as well as medicinal role in human history and it has been on the top ten lists of herbal sales among people For evaluating the effect of garlic on blood pressure ,we reviewed clinical trials published from 1982 until 2013 by searching in informative bank such as PubMed ،Ovid ، Elsevier Science , Google Scholar with keywords garlic , blood pressure, hypertension and herbal supplement The result of this review article showed that several clinical trials have suggested garlic lowers systolic and or diastolic blood pressure and has beneficial effect in controlling hypertension, but negative results also have been obtained in some of trials Blood pressure reducing properties of garlic have been linked to its hydrogen sulphide production and allicin content , liberated from alliin and the enzyme alliinase large scale trials are needed to investigate whether standardized garlic preparations could provide a safe alternative or complementary treatment option for hypertension in clinical practice Keyword: Garlic; Hypertension; Blood pressure; Herbal supplement disease Primary management of hypertension should include relevant lifestyle modifications such as increased exercise, weight loss and dietary changes which could incorporate dietary supplementation [1].Current medication therapy with standard antihypertensive medication is not always effective and leading to a large proportion of uncontrolled hypertension In addition, side effects of treatment may be influence treatment adherence For this reason, use of complementary and alternative therapies is high in patients with high blood pressure [2] Garlic (Allium sativum) has a long history of use as a pungent spice and as a foodstuff in numerous countries It has also been used for various medicinal purposes [3] Garlic has historically INTRODUCTION Hypertension that defined as a systolic blood pressure Greater than 140 mmHg and or a diastolic blood pressure Greater than 90 mmHg, is one of the major risk factors for cardiovascular morbidities including coronary artery disease , myocardial infarction and kidney disease, as well as for mortality [1] Hypertension affects one billion or one in three adults worldwide, and attributes to about 40% of cardiovascular related deaths , unfortunately more than 50% of hypertensive individuals are unaware of their condition [2] There are several factors that have been associated with hypertension such as smoking, obesity, inappropriate lifestyle and some chronic 92 Journal of Paramedical Sciences (JPS) Winter 2014 Vol.5, No.1 ISSN 2008-4978 been used to treat earaches, severe diarrhea, leprosy, deafness, constipation and parasitic infections, fever, fight infections and relieve stomach [4] The name “allium sativum” is derived from the Celtic word “all”, meaning burning or stinging, and the Latin “sativum” meaning planted or cultivated The English word, garlic, is derived from the Anglo-Saxon “gar-leac” or spear plant, referring to its flowering stalk [5] In Traditional Chinese Medicine, garlic is known as da suan It is considered a warm, bitter herb with particular effects on the Large Intestine, Spleen and Stomach meridians Garlic has been on the top ten lists of herbal sales for several years [6] Over the last 30 years, numerous clinical studies have been carried out to examine the effects of various garlic-based products containing dried garlic powder, garlic oil or garlic extract as the basal component on health This paper will review the effect of Garlic on Blood pressure allicin Allicin is further metabolized to vinyldithiines [8] Garlic is rich source of highly bioavailable selenium, which is thought to account, in part, for garlic’s antioxidant that is important for health Some growers add selenium to the soil to enhance garlic’s selenium content [9] Allicin and aliin is thought to be the most beneficial compound in terms of cardiovascular risk factors [10] Various garlic-based products are used in studies Raw garlic homogenate has been the major preparation of garlic subjected to scientific study, as because it is the commonest way of garlic consumption Raw garlic homogenate is essentially same as aqueous extract of garlic, which has been used in various scientific studies [11] Garlic oil also is used in studies , it is mostly prepared by steam-distillation process Steamdistilled garlic oil consists of the diallyl (57%), allyl methyl (37%) and dimethyl (6%) mono to hexa sulfides A typical commercial preparation of garlic oil contains diallyl disulfide (26%), diallyl trisulfide (19%), allyl methyl trisulfide (15%), allyl methyl disulfide (13%), diallyl tetrasulfide (8%), allyl methyl tetrasulfide (6%), dimethyl trisulfide (3%), penta sulfide (4%) and hexa sulfide (1%) [12] Another widely studied garlic preparation is aged garlic extract (AGE) Sliced raw garlic stored in 15–20% ethanol for 20 months is refereed to as AGE This whole process is supposed to cause considerable loss of allicin and increased activity of certain newer compounds, like S-allylcysteine , Sallylmercaptocysteine, allixin and selenium which are stable, highly bioavailable and significantly antioxidant [13] Another recently identified antioxidant compound of AGE is N-alpha-Larginine that is not present in raw garlic [12] Effect of garlic on blood pressure Many studies have explored effect of garlic on controlling blood pressure In a meta-analysis of seven placebo-controlled clinical trials using garlic powder supplementation, three studies showed a significant reduction in systolic blood pressure and four in diastolic blood pressure The overall pooled mean difference in the change in systolic blood pressure was 5-7% greater in the subjects who were treated with garlic than in those treated with placebo The reduction in MATERIALS AND METHODS Articles used in this study, were collected by searching in informative bank such as PubMed ، Ovid ، Elsevier Science , Google Scholar From 1982 until 2013 The keywords " Garlic , Blood pressure, Hypertension and Herbal supplement " were used for searching Studies were limited to english languages and clinicaltrials.gov was searched for ongoing trials From related articles, 37 articles related to the effect of garlic and blood pressure were extracted RESULT Chemical and biochemical structure of garlic Garlic contains Thirty-three sulfur compounds, several enzymes, seventeen amino acids, and minerals [7] It contains a higher concentration of sulfur compounds than any other Allium species The sulfur compounds are responsible both for garlic’s medical effects and its pungent odor Dried, powdered garlic contains approximately one percent alliin [7] One of the most biologically active compounds, allicin (diallyl disulfide) does not exist in garlic until it is crushed or cut, injury to the garlic bulb activates the enzyme allinase, which metabolizes alliin to 93 Journal of Paramedical Sciences (JPS) Winter 2014 Vol.5, No.1 ISSN 2008-4978 diastolic blood pressure in the garlic-treated subjects was slightly smaller [14] Table Summaries of human studies about effect of garlic on blood pressure References Intervention subjects Duration Dose Result Ried K 2013 [2] aged garlic extract hypertensive patients 12 weeks 960 mg/day Nakasone Y 2013[17] dried garlic homogenate 12 weeks 300 mg/day Sobenin IA 2009 [27] garlic powder tablets prehypertensive and mild hypertensive subjects men with mild or moderate hypertension 8-week 600 mg Turner B 2004 [28] Dried garlic powder Garlic tablet (Garlet) Healthy middle-aged individuals pregnant women 12-week 230 mg/day months 800 mg/day Qidwai, 2000 [30] Garlic in diet Healthy subjects Chronic intake 134gm/month Siegel G 1999 [18] garlic powder 4-year 900 mg/day McCrindle 1998 [31] Kwai(garlic pill) Cardiovascular disease patients pediatric patients, aged to 18 years, who had familial hyperlipidemia moderately hypercholesterolemic men weeks 900 mg/day months 7.2 gm/day subjects with mild to moderate hypercholesterolaemia and hypertension healthy adults 12 weeks 900 mg/day 5.5% decrease in systolic blood pressure and a modest reduction of diastolic blood pressure No changes 12 weeks 900 mg/day No changes patients with severe hypertension Acute 2400 mg significant decrease in diastolic blood pressure (p < 0.05) from 5-14 hours after the dose diastolic blood pressure decreased 9.5% (from 74 +/9 to 67 +/- mmHg) diastolic blood pressure fell from 102 to 89 mmHg (p less than 0.01) No changes Ziaei 2001 [29] during the third trimester of pregnancy garlet was effective in reducing the occurrence of hypertension (P=0.043), but it was no effective in preventing of preeclampsia individuals with blood pressures on the lower side consume more garlic in their diets ↓ BP (lowering in blood pressure by 7%) No changes Steiner 1996 [32] Aged garlic extract Simons 1995 [33] Kwai(garlic pill) Jain 1993 [34] Mcmahan, 1993 [35] Kwai(garlic pill) Garlic powder Kiesewetter 1991[36] Garlic powder Cardiovascular disease patients weeks 800 mg/day Auer 1990 [37] Kwai(garlic pill) patients with mild hypertension 12 weeks 600 mg/day Zimmerman1990[38] Kwai (garlic pill) hypertensive patients weeks 900 mg/day 94 reduction in systolic blood pressure -10.2±4.3 mmHg, P=0.03) ↓ hypertension in mild hypertensive subjects (4.6%; P